Impedance matching means matching a source impedance with a load impedance, so that power transported from a generator to a load is rendered maximum. A load impedance is often not matched with a line, which, in the case of radio frequency circuits, results in standing waves on the line, whereby the power may not be fully transferred from the generator to the load. On a line with a wave completely standing, for example, there can be no energy transportation. This effect may typically be prevented by two types of matching. First, loads may be matched resistively by means of resistors. This, however, incurs high loses and is basically only used when a certain impedance must be retained over very many parameters. This is often referred to as a so-called forced matching. A frequency-dependent method is represented by a use of reactances, wherein here too, depending on the quality of the reactances, losses are incurred, even if they are typically substantially smaller.
Matching circuits are often realized by means of discrete devices, which leads to substantial space requirements. Therefore, matching circuits, in particular integrated matching circuits, keeping the chip area required for the matching circuits as small as possible, are desired.